 This may be used with any factor of any type of chord, but rhythm is played so that the chord tones fall on the downbeats.In Bebop melodic improvisation, targeting often focused on the 9th, 11th and 13th of the chord - the colour tones - before resolving later in the phrase to a 7th chord tone.In bebop the 9th, 11th and 13th notes were often altered by adding sharps or flats to these notes.